MRCOOL DIY 12,000 BTU 5th Gen Ductless Mini Split Air Handler - Energy Star, 115V (DIY-12-HP-WMAH-115D25-O)

Stop sacrificing window space, natural light, and security with oversized window units that struggle to cool your larger rooms. The MRCOOL DIY 5th Gen 12,000 BTU Air Handler delivers sleek, wall-mounted climate control with the power to efficiently heat and cool spaces up to 550 sq. ft. - all without blocking your windows or compromising your room's aesthetics. This compact indoor unit mounts directly to your finished wall, providing professional-grade performance through heat, cool, dehumidify, and sleep modes that window units simply can't match.

Designed for DIY installation when paired with a compatible MRCOOL DIY 5th Gen 12K BTU condenser (sold separately), this air handler requires no special tools or HVAC experience. The pre-charged 25-foot DIY QuickConnect line set, filled with R-454B refrigerant, eliminates the need for vacuuming, saving you time, effort, and installation costs. Plus, the included DIYPRO cable enhances durability by removing the need for electrical conduit, protecting against outdoor elements and wildlife.

Take control your way - whether with the wireless remote, the SmartHVAC app for Apple and Android, or hands-free voice commands via Amazon Alexa and Google Assistant. The Gold Fin Condenser also provides enhanced corrosion resistance, making it an excellent choice for coastal environments. Designed with your comfort in mind, the system’s wireless remote features Follow Me technology, allowing the air handler to adjust based on the remote’s location for personalized comfort. Dry Mode adds another layer of convenience by reducing humidity and preventing excess condensation.

With 12,000 BTU of cooling and heating capacity, this Energy Star certified air handler delivers the power needed for master bedrooms, large home offices, retail spaces, restaurant dining areas, and rental properties. Protected with industry-leading warranties, including a limited lifetime warranty, a 7-year compressor warranty, and a 5-year parts warranty, you can trust in long-lasting performance. Experience an easier installation, smart technology, and year-round comfort with the 5th Generation MRCOOL DIY.

Best For:

• Homeowners with larger rooms - Wall-mounted design handles master bedrooms, large living rooms, bonus rooms, and home offices up to 550 sq. ft. while preserving window space, enhancing security, and maintaining room aesthetics.
• Property owners and landlords - Perfect for premium rental units, Airbnb suites, larger condominiums, and apartments where 12K BTU capacity adds value and delivers superior comfort without window-blocking equipment.
• Small to medium business owners - Ideal for retail stores, professional offices, salons, studios, and commercial spaces up to 550 sq. ft. where sleek wall-mounted units maintain professional appearance while delivering robust temperature control.
• Restaurant and hospitality operators - Provides powerful climate management for larger dining rooms, guest suites, and customer-facing areas where aesthetics matter and traditional window units aren't acceptable for bigger spaces.
• DIY enthusiasts upgrading capacity - Install yourself when paired with a compatible MRCOOL DIY 12K condenser using included hardware and video tutorials—step up to 12K power without HVAC professionals.
• Tech-savvy homeowners and businesses - Built-in SmartHVAC Wi-Fi enables smartphone control, automated scheduling, "Follow Me" sensing, and voice commands for modern, intelligent climate management in larger spaces.

What Makes this MRCOOL DIY 5th Gen Mini Split Air Handler Stand Out

• 12,000 BTU Power for Larger Spaces - Handles master bedrooms, large offices, and commercial areas up to 550 sq. ft. that 9K units struggle to maintain—delivers consistent comfort in spaces where smaller capacity falls short.
• Window-Free Wall Installation - Mounts directly to finished walls, preserving natural light, improving security, and maintaining room aesthetics while eliminating bulky, inefficient window units that block views.
• "Follow Me" Intelligent Comfort - Wireless remote acts as a mobile thermostat, reading temperature at its location and instructing the air handler to adjust output for personalized comfort exactly where you are.
• Smart Wi-Fi Control Anywhere - SmartHVAC smartphone app (iOS & Android) plus voice commands via Alexa and Google Assistant enable temperature adjustments, mode changes, and scheduling from anywhere.
• Built-In Dehumidification Mode - Dry Mode removes excess moisture from humid environments, improving indoor air quality and comfort during muggy weather without overcooling larger spaces.
• DIY-Friendly Installation - Designed for homeowner installation when paired with MRCOOL DIY 12K condenser and QuickConnect line set—no HVAC license, vacuum pumps, or specialized tools required.
• Industry-Leading Warranty Protection - Limited lifetime warranty backed by 7-year compressor and 5-year parts coverage demonstrates MRCOOL's engineering confidence and protects your investment.

Certifications & Safety Features

• Energy Star Certified - Meets rigorous EPA energy efficiency standards for reduced environmental impact and lower operational costs year-round.
• Intertek Listed (5031495) - Third-party certified for compliance with electrical safety, performance standards, and energy efficiency requirements.
• Limited Lifetime Warranty - Coverage on select components demonstrates manufacturer confidence and long-term investment protection.
• 7-Year Compressor Warranty - Extended protection on the core heating and cooling component for maximum peace of mind.
• 5-Year Parts Warranty - Comprehensive coverage on system components protects against unexpected repair expenses.
• 115V Standard Residential Operation - Safe operation on conventional household electrical service without expensive panel upgrades or dedicated circuits.